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At least 199 records · Page 11Linked to original sources
PubMed1990

Relation of blood viscosity to demographic and physiologic variables and to cardiovascular risk factors in apparently normal adults.

Although increased blood viscosity occurs in several cardiovascular diseases, little is known of factors influencing blood rheology in normal adults. Accordingly, we examined the relations of whole blood viscosity (WBV) to its rheologic determinants (hematocrit level, plasma viscosity, protein concentration, and red cell aggregability and rigidity), to demographic and laboratory variables, and to cardiovascular risk factors in 128 normotensive employed adults. Hematocrit levels accounted for 67-84% of variability of WBV at shear rates from 208 to 0.1 sec-1 with lesser contributions from plasma viscosity, red cell aggregability, and rigidity (multiple r = 0.95-0.97); WBV was predicted accurately from standard measurements of hematocrit and total plasma protein levels (multiple r = 0.78-0.92 in "learning" and "test" analysis). Male sex, obesity, dietary Na+ intake, and increasing age had additive effects on WBV (multiple r greater than or equal to 0.59, p less than 0.00001); the last three of these factors and black race independently predicted plasma viscosity (multiple r = 0.36, p less than 0.001). Among regulators of plasma volume, plasma renin activity and urinary Na+ excretion bore independent positive relations to WBV. Diastolic and mean blood pressures were independent predictors of WBV and hematocrit levels (all p less than 0.05). Conventional risk factors (e.g., triglycerides, obesity, and cholesterol levels) were positively related to WBV or plasma viscosity. Thus, in apparently normal adults, 1) WBV or plasma viscosity are increased by male sex, obesity, high sodium intake, aging, and black race, 2) WBV is positively related to plasma renin activity, 3) WBV or plasma viscosity are related to diastolic and mean blood pressures, triglycerides and cholesterol concentrations, and 4) WBV can be predicted from simple measurements of hematocrit and total plasma protein levels.

Adult↗
PubMed2004

Effects of two anti-inflammatory drugs on physiologic variables and milk production in cows with endotoxin-induced mastitis.

OBJECTIVE: To determine the effects of 2 anti-inflammatory drugs in lactating Holstein cows with endotoxin-induced mastitis. ANIMALS: 30 multiparous Holstein cows that had been lactating for 30 to 60 days. PROCEDURE: Bacterial culture of milk samples and physical examinations established that study cows were in good health and free of mastitis. Mastitis was induced in 1 front mammary gland by intramammary administration of purified bacterial endotoxin. Cows were allocated into 1 of 3 treatment groups: untreated endotoxic mastitis (n = 9), endotoxic mastitis plus flunixin meglumine (9), and endotoxic mastitis plus isoflupredone acetate (10). Heart rate, rectal temperature, mammary surface area, and rumen motility were recorded hourly for 14 hours following endotoxin administration. Flunixin meglumine or isoflupredone acetate was administered after mammary swelling and rectal temperature > or = 40 degrees C had developed. Milk production was evaluated from 5 days before to 10 days after induction of mastitis. RESULTS: Neither drug ameliorated loss of milk production or swelling of the affected mammary gland. Both drugs reduced mean heart rate during the 14 hours following endotoxin administration, compared with untreated control cows. Cows treated with flunixin meglumine had increased rumen motility and decreased rectal temperature during the same period, compared with all other cows. CONCLUSIONS AND CLINICAL RELEVANCE: Neither drug enhanced recovery of milk production following endotoxin-induced mastitis. Flunixin meglumine decreased rectal temperature, whereas isoflupredone did not; however, it has not been established that reduction of fever is beneficial to cows with naturally occurring mastitis.

Animals↗
PubMed2002

Influence of dietary conjugated linoleic acid on growth, meat quality, lipogenesis, plasma leptin and physiological variables of lipid metabolism in rabbits.

We investigated the effects of conjugated linoleic acid (CLA) supplementation on growth, feed efficiency, carcass characteristics, meat quality, lipogenesis, and lipid metabolism in rabbits. One hundred forty-four New Zealand White rabbits, half males, half females, age 55 d, mean 1.8 kg BW, were randomly assigned to three weight- and sex-balanced feeding groups in which conventional pelleted diets were supplemented with 0, 0.25, or 0.5% of a CLA preparation. The CLA preparation contained 65% CLA isomers. Twelve rabbits (six males and six females from each group) were slaughtered at each of three slaughtering trials (2.5, 2.8, and 3.1 kg BW, or 76, 90, and 104 d of age). Conjugated linoleic acid supplementation did not influence growth performance (P > or = 0.05) or carcass characteristics but reduced perirenal fat at heavier slaughtering weights (P = 0.09 at 2.8 kg BW; P < 0.01 at 3.1 kg BW). Conjugated linoleic acid reduced acetyl-CoA-carboxylase (CBX) activity in liver (P < 0.05) and adipose tissues (P < 0.01) but did not influence malic enzyme (ME) or glucose-6-phosphate dehydrogenase activity. Significant differences were found between sex in interscapular fat (P < 0.05) for CBX, in perirenal (P < 0.01) and interscapular (P < 0.05) fat for ME, and a tendency (P = 0.070) in liver for glucose-6-phosphate dehydrogenase. The oxidative stability of longissimus lumborum muscle was increased at the higher level of supplementation (P < 0.05). Conjugated linoleic acid reduced (P < 0.05) triglycerides and total cholesterol in plasma with a trend to increased serum leptin (P = 0.06). Plasma triglycerides were higher in males than females (P < 0.01) and plasma leptin tended to be higher in females (2.57 vs. 2.13 ng/ml, P = 0.06). It is concluded that dietary CLA reduced carcass fat in rabbits slaughtered at 2.8 kg or above and altered lipid metabolism to produce lower concentrations of serum triglycerides and total cholesterol and higher concentrations of leptin.

Animal Feed↗
PubMedDate not supplied

Nasal problems in wood furniture workers. A study of symptoms and physiological variables.

The occurrence of symptoms from the upper airways in the furniture industry was studied by means of a questionnaire which was answered by 676 wood furniture workers from 50 different factories. Twenty per cent reported nasal hypersecretion and 40% nasal obstruction. A randomized sample of 61 workers was investigated further. Rhinomanometry confirmed the sense of nasal obstruction objectively. The air-conditioning capacity was normal. Nasal clearance was reduced in 54% of the wood-workers. Spirometry revealed a significantly reduced forced expiratory vital capacity in the investigated workers, compared with a normal reference material. The mean concentration of wood dust was 2.0 mg/m3 air (range 0.30-5.06 mg/m3). These results have initiated further allergological and morphological studies in wood furniture workers.

Air Pollutants, Occupational↗
PubMed1987

Variation of behavioral and physiological variables in children attending kindergarten and primary school.

Twenty-one children aged 5-6 years (mean age: 71.2 months; S.D. = 2.7) were videotaped in 4 different kindergartens throughout the school day for a period of one week. Eighteen of these children were then followed up after the summer holidays and videotaped for one week while attending the first year of primary school. The behaviors measured for each child were yawning and general motor activity. It was found that: (1) The frequency of yawning appears to be 5 times higher in the first year of primary school than in the last year of kindergarten; (2) Throughout the school-day the percentage of yawning children is higher in the first year of primary school, with the exception of the 1400-1430 period; (3) In the first year of primary school, the percentage of yawning children and the frequency of yawning peak between 900 and 930 and 1430 and 1500; (4) In this school institution the percentage of children who get up from their chair and spontaneously move above increases from the beginning to the end of each school-day. Three cardio-vascular variables were investigated in 17 children of the sample population: heart rate, systolic and diastolic blood pressure. We found that: (1) The lowest values for heart rate in the first year of primary school are in agreement with the classical data of child development, as the children are 5-6 months older than in the last year of kindergarten. However, this is not the case at 1400 when the heart rate peaks at a higher level in the first year of primary school; (2) If the evolution in time of the blood pressure agrees in both institutions with the classical data of human chronobiology, i.e. the maximum values at 1400, the differences in mean level at all times during the school day between both institutions do not agree with what is commonly accepted, i.e. an increase in blood pressure with age; (3) The amplitude of the variations of the heart rate and blood pressure from one 30-min period to another throughout the school day is significantly higher in primary school. The comparison of the data obtained in both school institutions suggests that the observed differences are related to sharp modifications in school rhythms and constraints when the children go from the last year of kindergarten to the first year of primary school.

Aging↗
PubMed2000

The effects of an application of suncream on selected physiological variables during exercise in the heat.

BACKGROUND: The purpose of this study was to investigate the effects of an application of suncream on mean skin temperature (MST), rectal temperature (Tre), oxygen consumption and heart rate during exercise in the heat. METHODS: Twenty-two male subjects underwent two steady state exercise tests (55% of maximum oxygen consumption, mean work rate 153 watts) for 40 minutes (following a 5 minute warm-up), under two treatment conditions at the same ambient temperature (32 degrees C, 54% relative humidity). One treatment involved wearing an application of suncream (SC) while the other treatment did not (NSC). Suncream was applied in the amount of 30 ml/m2 of body surface area. RESULTS: Results of this study indicated that an application of suncream significantly reduced MST, on average. 31 degrees C, during exercise in the heat (p = 0.03). However, further statistical analysis revealed that this was a function of a significant interaction effect (p = 0.001) (main effect is sunscreen; interaction effect sunscreen plus temperature). MST was lower for the SC condition versus NSC over all time measurements. Results also showed a significant difference in the mean core to skin temperature gradient (p = 0.001), with a greater gradient existing in the SC condition. There did not appear to be any effect of suncream on ventilation, rectal temperature, oxygen consumption, lactate levels, sweat loss, percent plasma volume change, rating of perceived exertion, or respiratory exchange ratio. Interestingly, although not statistically significant (p = 0.18), rectal temperature remained lower, on average 0.1 degree C, under the SC condition for every measurement throughout the exercise session. CONCLUSIONS: In conclusion, results of this preliminary study suggest that an application of suncream does not impair heat dissipation as indicated by a decreased MST and increased core to skin thermal gradient.

Adult↗
PubMed2000

The influence of isolation on psychological and physiological variables.

BACKGROUND: Human behavior is temporally organized by an endogenous "biological clock," and the alternation between activity and rest is an integral part of this system. Like all other biological functions, the system is only capable of adapting to external stimuli to a limited (and recognizable) extent. HYPOTHESIS: In space, astronauts are kept in a relatively isolated and extreme environment. Under these conditions the circadian system is disturbed and specific countermeasures must be invoked in order to avoid negative consequences on sleep, mood and performance. METHOD: The results of isolation experiments will be compared with studies in space focusing on the circadian course of variables such as body core temperature, sleep-wake patterns, mood, and performance. RESULTS: Subjects in isolation can show disturbances of sleep, mood and vigilance if their biological rhythms run "out of phase." CONCLUSIONS: A strict 24-h time schedule should be kept with regard to environmental, as well as behavioral influences to insure adequate and restful sleep and optimal levels of waking performance and psychological well-being.

Adaptation, Psychological↗
PubMed1975

Temporal intrapersonal physiological variability of cholinesterase activity in human plasma and erythrocytes.

Erythrocyte and plasma cholinesterase activities were measured biweekly in one group of 22 subjects for a year and daily for three weeks in another group of nine men. The average range [i.e., (range/mean) X 100] of activity of erythrocyte cholinesterase in men during a year was 8% and during three weeks was 5%. For plasma, the corresponding values were 25% and 12%. The average ranges for erythrocyte and plasma cholinesterase activity in women during a year were 12% and 24%. Erythrocyte cholinesterase activity varies less than do hematocrit, hemoglobin, or erythrocyte count.

Adult↗
PubMed1976

Physiological variables during 10 years of endurance exercise.

The reported decline in Physical Working Capacity (PWC) max is from 9-15 percent during the ages of 45 to 55 years. The use of vigorous physical activity to prevent this decline and to possibly protect against fatal myocardial infarction has been suggested. The purpose of this study was to investigate the effect of an endurance type exercise program on the maximal PWC of middle-aged men during a 10 year span. Sixteen men, initially 32-56 years (M-44.6), were trained with running or swimming at an intensity above 60 percent of VO2 max during a 10 year period. The average weekly running distance was 15 miles (25 km). The criterion for PWC was directly measured VO2 using the Douglas Bag/Scholander technique. No changes were observed in body weight, resting heart rate (HR), or resting blood pressure (BP). Maximal HR declined 7 beats per minute in 10 years. Pulmonary ventilation (STPD) increased approximately 18 percent. Mean VO2 max was essentially unchanged, 3.376 and 3.303 1/min STPD. VO2 max related to body weight was 43.7 initially and 44.4 ml/min-kg after 10 years. It was concluded that the usual 9-15 percent decline in PWC or VO2 max from age 45 to 55 years can be forestalled by regular endurance exercise. The results may have implications for protecting against heart attacks.

Adult↗